Lithium secondary battery

A lithium secondary battery and electrolyte technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve the problems of battery internal resistance increase and power failure, and achieve the effect of suppressing increase and preventing sudden power failure.

Pending Publication Date: 2021-01-08
LG ENERGY SOLUTION LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Generally, a method of increasing the electrode rolling ratio or further adding salt to the electrolyte is used to obtain a high-voltage and high-capacity small lithium secondary battery. resistance increases, problems such as sudden power failure during use often occur

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0093] 1. Embodiment 1: Lithium secondary battery preparation

[0094] Prepare the positive electrode active material, wherein the average particle size (D 50 ) is the first lithium cobalt oxide of 2.5 μm and the average particle size (D 50 ) is the second lithium cobalt oxide of 11 μm. In this case, the first lithium cobalt oxide and the second lithium cobalt oxide each containing aluminum at a concentration of 3,100 ppm were used.

[0095] Then, the positive electrode active material, carbon black as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder were mixed in a weight ratio of 97.59:1.1:1.31, and then N-methyl-2- Pyrrolidone (NMP) to prepare positive electrode active material slurry (solid component content: 50% by weight). A 12 μm-thick aluminum (Al) thin film as a positive electrode collector was coated with the positive electrode active material slurry, dried, and then rolled to prepare a positive electrode.

[0096] Negative electrode active mate...

Embodiment 2

[0101] A lithium secondary battery was prepared in the same manner as in Example 1, except that a cathode active material in which the second lithium cobalt oxide and the second lithium cobalt oxide each contained aluminum at a concentration of 3,900 ppm was used.

experiment example 1

[0108] 1. Experimental Example 1: Continuous charging evaluation

[0109] Each of the coin-type lithium secondary batteries prepared in Examples 1 and 2 and Comparative Example 1 was activated at a constant current (CC) of 0.7C. After that, each lithium secondary battery was charged to 4.45V at a CC of 0.7C under constant current-constant voltage (CC-CV) conditions at 25°C, then cut off at a current of 0.05C, and discharged to 3.0V at a CC of 0.2C. V.

[0110] Next, each battery was continuously charged at a CC of 0.5C to 4.45V for 28 days under constant current-constant voltage (CC-CV) conditions at high temperature (45°C), and measured every 5 days using a 300gf flat plate thickness gauge once the thickness of each cell, the results are presented in figure 1 .

[0111] see figure 1 , in the case of continuous charging of each lithium secondary battery, it can be confirmed that since the expansion of the secondary battery of Comparative Example 1 exceeds that of the secon...

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Abstract

The present invention provides a lithium secondary battery comprising: a positive electrode comprising aluminum-doped bimodal lithium cobalt oxide which comprises a first lithium cobalt oxide and a second lithium cobalt oxide having different average particle sizes (D50) from each other; a negative electrode comprising a bimodal graphite which comprises a first graphite and a second graphite having different average particle sizes (D50) from each other; and a first additive which is a nitrile-based compound, wherein the first lithium cobalt oxide and the second lithium cobalt oxide each independently comprise aluminum with a concentration of 2500 to 4000 ppm.

Description

technical field [0001] Cross References to Related Applications [0002] This application claims priority from Korean Patent Application No. 2019-0009467 filed on January 24, 2019, the disclosure of which is incorporated herein by reference. technical field [0003] The present invention relates to lithium secondary batteries, particularly lithium secondary batteries having improved resistance characteristics. Background technique [0004] Recently, there has been a growing interest in energy storage technologies. For example, research and development efforts for energy storage technology have been gradually materialized while extending the application of energy storage technology to mobile phones, camcorders, notebook computers, and even electric vehicles. Electrochemical devices have received the most attention in the field of energy storage technology, and research on rechargeable secondary batteries among these electrochemical devices has been actively conducted. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/525H01M4/587H01M10/0567H01M10/0525
CPCH01M10/0567H01M10/0525H01M4/525H01M4/587Y02E60/10H01M4/364H01M2300/004
Inventor 郑桃花卢泰均金基雄李羽卨李允载宋政桓
Owner LG ENERGY SOLUTION LTD
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